Technical Field
The present disclosure generally relates to electronic circuits and, more particularly, to the protection of an integrated circuit against fault injections by laser attack.
Description of the Related Art
In many applications, electronic circuits manipulate secret data, that is, data to which access is desired to be reserved to certain users or circuits.
There exist many methods, called attacks, to attempt discovering or pirating secret data. Among such attacks, so-called fault injection attacks comprise disturbing the circuit operation by acting on one or a plurality of bits that it manipulates. A category of fault injection attacks more particularly targeted by the present disclosure is laser attacks, which comprise pointing a laser beam on logic elements of the circuit to switch the bits processed by these elements. Examining the consequence of such an attack on the circuit behavior, be it by direct examination of the data supplied by the circuit or by indirect examination by executing a side channel attack, may enable the attacker to discover a secret.
Laser attacks generally are attacks carried out from the rear surface of the integrated circuit after a treatment comprising eroding the substrate.
To counter this type of attack, integrated circuits are generally equipped with detectors in the form of lead frames (mesh) or of photocurrent or current detectors. Another category of detectors more particularly targeted by the present disclosure comprises using flip-flop-type logic elements having as an only function to detect a state switching representative of an incidental or intentional disturbance.
The protection of integrated circuits against laser attacks needs to be improved.